Does an attack still succeed if the target is immune to the condition?

Question

Working on a homebrew for Battleragers, and here's something about their armor that got me thinking:

Battlerager Armor SCAG p121

When you choose this path at 3rd level, you gain the ability to use spiked armor as a weapon.

While you are wearing spiked armor and are raging, you can use a bonus action to make one melee weapon attack with your armor spikes at a target within 5 feet of you. If the attack hits, the spikes deal 1d4 piercing damage. You use your Strength modifier for the attack and damage rolls.

Additionally, when you use the Attack action to grapple a creature, the target takes 3 piercing damage if your grapple check succeeds.

Bold part is what I'm wondering. Say a Battlerager is fighting a Ghost, who is immune to the grappled condition. But even if they are immune they do still need to make a contested check, and sure the ghost can choose to fail it willingly thinking that it's immune to grapple so why bother? But if they fail, willing or not, that still means the battlerager's grapple check succeeded, even if the condition doesn't stick. So wouldn't they still be able to inflict that damage?

Answer 1

You can still hit an enemy with an attack they're immune to, but because you land the attack additional damage from other sources also apply, which could potentially hurt the target.

In this instance, you "hit" with your grapple, which Ghosts are immune to. But they aren't immune to Piercing damage, so they'll take that damage since they were hit by the grapple.